Implement useSDKEvents hook for event stream integration #11771

function useSDKEvents(sessionId: string | null, dispatch: Dispatch<Action>) {
  useEffect(() => {
    if (!sessionId) return
    
    const abortController = new AbortController()
    
    ;(async () => {
      const client = createOpencodeClient({
        baseURL: `http://localhost:${port}`,
        // auth headers...
      })
      
      const events = await client.event.subscribe({
        signal: abortController.signal
      })
      
      for await (const event of events.stream) {
        // Dispatch actions based on event type
        switch (event.type) {
          case 'part.updated':
            handlePartUpdated(event, dispatch)
            break
          case 'message.created':
            handleMessageCreated(event, dispatch)
            break
          // etc.
        }
      }
    })()
    
    return () => abortController.abort()
  }, [sessionId, dispatch])
}

function handlePartUpdated(event: PartUpdatedEvent, dispatch: Dispatch<Action>) {
  const part = event.properties.part
  
  // If this is a task tool, extract child session ID from metadata
  if (part.tool === 'task' && part.state.metadata?.sessionId) {
    dispatch({
      type: 'TASK_REGISTER_CHILD_SESSION',
      taskId: part.callID,
      childSessionId: part.state.metadata.sessionId
    })
  }
  
  // If this is from a child session, find parent task
  if (part.sessionID !== currentSessionId) {
    const parentTaskId = childSessionToTask.get(part.sessionID)
    if (parentTaskId) {
      dispatch({
        type: 'TASK_UPDATE_CHILD',
        taskId: parentTaskId,
        childTool: {
          name: part.tool,
          summary: part.state.title || 'running',
          status: part.state.status
        }
      })
    }
  }
}

// In reducer or context
const childSessionToTask = new Map<string, string>()  // child session ID -> task call ID
const taskToChildSession = new Map<string, string>()  // task call ID -> child session ID